Stopping an Attack - Does size matter?

I found this site and the information very interesting with great analysis of actual real world factors in stopping or dropping an assailant.

http://www.firearmstactical.com/hwfe.htm
The main thing I took from it was to make sure that you punch a hole in the target at least 12 inches deep regardless of caliber.  I knew this already but this also explained that often simply notifying the target that it has been hit usually causes them to fall down.  So the object is to actually hit your target with anything even if it is a .22 versus sending a fusillade of .44 magnum wide of the target.  Somehow a .22 coming out of an AR15 at 2700 FPS  is worthy of respect by big caliber handgun aficionados while a .22 coming in at 1000 FPS from a pistol is a mouse gun according to same big caliber adherents.  By the way, many of these same guys will run like a scalded dog when chased by a wasp or hornet that hasn't even stung them yet but apparently have no fear of that said mouse round that they have never actually faced.  Where is the truth on this.  I think most people that are shot will take note rather soon especially when reminded with multiple strikes whether it is a .22 or a .45.  Personally I am a fan of the .22 in all of it's incarnations such as the .22LR,.22 WMR, .223, 5.56 AR-15, 5.45 AK74, 5.7mm FNH 5.7 & P90.